Municipal Wastewater and Sludge Treatment
Appleton – Glenwood, NL
Glenwood and Appleton are two towns on opposite sides of the Gander River in Newfoundland. Both towns had ageing, overloaded sewage systems which could no longer meet the environmental regulations required for discharge into the Gander River.
Reed Bed technology can be used alone or in combination with other technologies to achieve one or more stages of sewage treatment. Mr. Glenn Sharp, P.Eng was the lead engineer on a proposal to design and build an Engineered Wetland as an environmentally friendly sewage treatment alternative.
The system successfully treats the waste, such that the resultant clean water can be safely discharged into the sensitive river system, in accordance with all the relevant environmental legislation.
Since commissioned in 2006, the system has continued to perform above the design expectations. All effluent sample analysis shows that the output provides more treatment than the requirements for secondary sewage treatment, and even performs on a yearly average at a tertiary treatment level. These results indicate a very successful secondary treatment project. (see table)
The effluent from both towns is pumped to the treatment facility where it passes througha grinder and a spiral lift screen to remove non-organic materials. The flow then enters a series of settling chambers where solids and suspended solid settle out.
During times of high infiltration, the flow is split by a weir that sends the main flow to the main wetland treatment beds and any excess to the storm water treatment bed. There is no bypass on this system. The wetlands reduce the contaminants by biological treatment. The two flows are recombined at the end of the system and discharged to the Gander River.
Other than the screen and grinder there are no mechanical or electrical components. No electricity or chemicals are required for treatment.
Sludge from the settling chambers is pumped to the sludge treatment wetland cells where it is mineralized by the plants resulting in a compost-like end product that can be used for landscaping. With treating the solids as well as the liquids, with no by-pass, this is truly a complete treatment system.
The project received numerous awards and recognition: In 2008, the town of Appleton received the Provincial Environmental Award; in 2010 the project received the Federation of Canadian Municipalities award for Leadership in Wastewater and Stormwater Design; also in 2010 it received the PEGNL Professional Engineering & Geoscientists of Newfoundland Environmental Award.
Second Year Average Tested Data – Appleton/Glenwood Engineered Wetland
|Parameter||Inlet||Wetland Outlet||Wetland Reduction||Down River Outlet||Down River Reduction||Standard|
|BOD (mg/l)||210.7||9.2||95.7%||1.5||99.3%||20 mg/l|
|TSS (mg/l)||1390.7||3.2||99.8%||1.0||99.9%||30 mg/l|
|Nitrogen (ammonia) (mg/l)||11.4||6.0||47.1%||0.3||97.8%||2.0 mg/l|
|Total Phosphorous (mg/l)||1.3||0.6||58.3%||0.01||99.2%||1.0 mg/l|
|Total Coliform (MPN/100 ml)||2,364,000||59,400||97.5%||190||100%||5,000|
|Fecal Coliform (MPN/100 ml)||1,181,400||27,000||97.7%||110||100%||1,000|